1. Field of the Invention
The present invention relates to a liquid crystal polyester composition comprising a liquid crystal polyester, a plate-like filler and a fibrous filler.
2. Related Background Art
Liquid crystal polyesters have excellent melt flow properties and high heat resistance, strength and rigidity, and are therefore suitably used as injection molding materials for production of electrical and electronic components. However, because liquid crystal polyesters tend to have their molecular chains oriented in the direction of flow during molding, this results in anisotropy of the shrinkage and expansion coefficients and the mechanical properties of compacts, tending to result in problems of warping and cracking (weld cracking). Mixture of plate-like fillers and fibrous fillers to liquid crystal polyesters has been investigated with the aim of avoiding these problems. For example, Japanese Unexamined Patent Application Publication No. 2002-294038 describes a liquid crystal polyester composition comprising 10-100 parts by weight of a plate-like inorganic filler with a mean particle size of 5-20 μm and 10-100 parts by weight of a fibrous inorganic filler, with respect to 100 parts by weight of the liquid crystal polyester, and the weight ratio of the content of the fibrous filler to the content of the plate-like filler is greater than 0 and less than 0.5, or greater than 1.6 and less than 10. Also, International Patent Publication No. WO2008/023839 describes a liquid crystal polyester composition comprising 30-40 wt % of a plate-like filler with a mean particle size of 0.5-200 μm and 10-20 wt % of a fibrous filler, with respect to the total amount of the liquid crystal polyester composition, with a total content of 40-60 wt % for both. Also, Japanese Unexamined Patent Application Publication No. 2010-003661 describes a liquid crystal polyester composition comprising 25-35 wt % of a plate-like inorganic filler and 10-25 wt % of a fibrous filler, with respect to the total amount of the liquid crystal polyester composition, with a total content of 40-50 wt % for both.